fix bugs with fab showing/hiding on scroll

app/src/main/java/com/keylesspalace/tusky/NotificationsFragment.java

@@ -19,7 +19,9 @@ import android.content.Context;
 import android.content.SharedPreferences;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.support.annotation.Nullable;
+import android.support.design.widget.FloatingActionButton;
 import android.support.design.widget.TabLayout;
 import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.widget.DividerItemDecoration;
@@ -40,15 +42,17 @@ import retrofit2.Response;
 
 public class NotificationsFragment extends SFragment implements
         SwipeRefreshLayout.OnRefreshListener, StatusActionListener, StatusRemoveListener,
-        NotificationsAdapter.NotificationActionListener {
+        NotificationsAdapter.NotificationActionListener, SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "Notifications"; // logging tag
 
     private SwipeRefreshLayout swipeRefreshLayout;
     private LinearLayoutManager layoutManager;
+    private RecyclerView recyclerView;
     private EndlessOnScrollListener scrollListener;
     private NotificationsAdapter adapter;
     private TabLayout.OnTabSelectedListener onTabSelectedListener;
     private Call<List<Notification>> listCall;
+    private boolean hideFab;
 
     public static NotificationsFragment newInstance() {
         NotificationsFragment fragment = new NotificationsFragment();
@@ -60,7 +64,7 @@ public class NotificationsFragment extends SFragment implements
     @Nullable
     @Override
     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
-             @Nullable Bundle savedInstanceState) {
+                             @Nullable Bundle savedInstanceState) {
         View rootView = inflater.inflate(R.layout.fragment_timeline, container, false);
 
         // Setup the SwipeRefreshLayout.
@@ -68,7 +72,7 @@ public class NotificationsFragment extends SFragment implements
         swipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_refresh_layout);
         swipeRefreshLayout.setOnRefreshListener(this);
         // Setup the RecyclerView.
-        RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
+        recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
         recyclerView.setHasFixedSize(true);
         layoutManager = new LinearLayoutManager(context);
         recyclerView.setLayoutManager(layoutManager);
@@ -78,19 +82,7 @@ public class NotificationsFragment extends SFragment implements
                 R.drawable.status_divider_dark);
         divider.setDrawable(drawable);
         recyclerView.addItemDecoration(divider);
-        scrollListener = new EndlessOnScrollListener(layoutManager) {
+
-            @Override
-            public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
-                NotificationsAdapter adapter = (NotificationsAdapter) view.getAdapter();
-                Notification notification = adapter.getItem(adapter.getItemCount() - 2);
-                if (notification != null) {
-                    sendFetchNotificationsRequest(notification.id, null);
-                } else {
-                    sendFetchNotificationsRequest();
-                }
-            }
-        };
-        recyclerView.addOnScrollListener(scrollListener);
         adapter = new NotificationsAdapter(this, this);
         recyclerView.setAdapter(adapter);
 
@@ -112,6 +104,51 @@ public class NotificationsFragment extends SFragment implements
         return rootView;
     }
 
+    @Override
+    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+
+        /* This is delayed until onActivityCreated solely because MainActivity.composeButton isn't
+         * guaranteed to be set until then.
+         * Use a modified scroll listener that both loads more notifications as it goes, and hides
+         * the compose button on down-scroll. */
+        MainActivity activity = (MainActivity) getActivity();
+        final FloatingActionButton composeButton = activity.composeButton;
+        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(
+                activity);
+        preferences.registerOnSharedPreferenceChangeListener(this);
+        hideFab = preferences.getBoolean("fabHide", false);
+        scrollListener = new EndlessOnScrollListener(layoutManager) {
+            @Override
+            public void onScrolled(RecyclerView view, int dx, int dy) {
+                super.onScrolled(view, dx, dy);
+
+                if (hideFab) {
+                    if (dy > 0 && composeButton.isShown()) {
+                        composeButton.hide(); // hides the button if we're scrolling down
+                    } else if (dy < 0 && !composeButton.isShown()) {
+                        composeButton.show(); // shows it if we are scrolling up
+                    }
+                } else if (!composeButton.isShown()) {
+                    composeButton.show();
+                }
+            }
+
+            @Override
+            public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
+                NotificationsAdapter adapter = (NotificationsAdapter) view.getAdapter();
+                Notification notification = adapter.getItem(adapter.getItemCount() - 2);
+                if (notification != null) {
+                    sendFetchNotificationsRequest(notification.id, null);
+                } else {
+                    sendFetchNotificationsRequest();
+                }
+            }
+        };
+
+        recyclerView.addOnScrollListener(scrollListener);
+    }
+
     @Override
     public void onDestroy() {
         super.onDestroy();
@@ -245,4 +282,11 @@ public class NotificationsFragment extends SFragment implements
     public void onViewAccount(String id) {
         super.viewAccount(id);
     }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+        if(key.equals("fabHide")) {
+            hideFab = sharedPreferences.getBoolean("fabHide", false);
+        }
+    }
 }

app/src/main/java/com/keylesspalace/tusky/TimelineFragment.java

@@ -39,7 +39,7 @@ import retrofit2.Call;
 import retrofit2.Callback;
 
 public class TimelineFragment extends SFragment implements
-        SwipeRefreshLayout.OnRefreshListener, StatusActionListener, StatusRemoveListener {
+        SwipeRefreshLayout.OnRefreshListener, StatusActionListener, StatusRemoveListener, SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "Timeline"; // logging tag
 
     private Call<List<Status>> listCall;
@@ -61,6 +61,7 @@ public class TimelineFragment extends SFragment implements
     private LinearLayoutManager layoutManager;
     private EndlessOnScrollListener scrollListener;
     private TabLayout.OnTabSelectedListener onTabSelectedListener;
+    private boolean hideFab;
 
     public static TimelineFragment newInstance(Kind kind) {
         TimelineFragment fragment = new TimelineFragment();
@@ -152,17 +153,21 @@ public class TimelineFragment extends SFragment implements
             final FloatingActionButton composeButton = activity.composeButton;
             final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(
                     activity);
+            preferences.registerOnSharedPreferenceChangeListener(this);
+            hideFab = preferences.getBoolean("fabHide", false);
             scrollListener = new EndlessOnScrollListener(layoutManager) {
                 @Override
                 public void onScrolled(RecyclerView view, int dx, int dy) {
                     super.onScrolled(view, dx, dy);
 
-                    if (preferences.getBoolean("fabHide", false)) {
+                    if (hideFab) {
                         if (dy > 0 && composeButton.isShown()) {
                             composeButton.hide(); // hides the button if we're scrolling down
                         } else if (dy < 0 && !composeButton.isShown()) {
                             composeButton.show(); // shows it if we are scrolling up
                         }
+                    } else if (!composeButton.isShown()) {
+                        composeButton.show();
                     }
                 }
 
@@ -358,4 +363,11 @@ public class TimelineFragment extends SFragment implements
         }
         super.viewAccount(id);
     }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+        if(key.equals("fabHide")) {
+            hideFab = sharedPreferences.getBoolean("fabHide", false);
+        }
+    }
 }